Cutting out meat and dairy for as little as a month could have measurable benefits for long-term health, according to new research.
Adults who followed a vegan diet for four weeks showed notable DNA changes associated with reduced inflammation and slower biological aging when compared with participants eating meat-heavy meals.
The researchers set out to determine whether a short-term shift in diet could alter how the body functions at a cellular level. Their findings suggest that people avoiding animal products developed biological signals tied to a calmer, less inflamed immune response.
The plant-based diet was also linked to lower activity in genes connected to cancer-related pathways, while markers associated with biological aging appeared to slow. Together, the results highlight how rapidly food choices may influence cells and, potentially, future disease risk.
For the study, published in the journal MedComm, scientists randomly placed 48 adults on either a vegan diet or a meat-rich diet for one month. The two meal plans were designed with comparable calorie levels to help ensure that weight loss did not skew the outcome.
Blood samples were collected from participants before and after the four-week trial, allowing researchers to analyze whether the dietary changes had left detectable marks on their DNA.
The team examined more than 800,000 sites across the genome where DNA methylation can occur — a chemical process that helps regulate whether certain genes are turned on or off.
The analysis found that the vegan diet was associated with fewer cells that promote inflammation and a higher presence of cells that help regulate and balance the immune system.
Researchers found that people who went vegan for four weeks saw DNA changes linked to lower inflammation and slower aging compared with those eating meat-rich diets
Going meatless also appeared to suppress genes linked to cancer pathways while boosting genetic activity tied to lower cholesterol, better insulin response and stronger DNA repair.
Scientists have developed ‘biological age clocks’ that use DNA to reveal how quickly the body is aging beneath the surface and in the one-month study, the vegan diet appeared to slow that clock.
When someone’s biological age is ahead of their actual age, it can signal a higher risk of disease later in life.
‘These findings reinforce the idea that not all measures of biological aging capture the same biology,’ researcher Jerome Mertens said.
‘The clocks associated with disease risk and overall health consistently pointed in the same direction, suggesting the dietary changes were influencing pathways tied to health rather than simply the passage of time.’
However, the study was small and the genetic changes were modest, so larger, longer-term studies are needed to see whether going vegan can truly cut disease risk.
The study also wasn’t limited to clean, whole foods – participants could eat vegan processed snacks, including granola bars, to meet their calorie goals. A similar study with a different diet could produce different results.
Even so, the findings offer an early glimpse at how quickly plant-based eating may reshape the body’s cells in just four weeks.
‘Our study adds to growing evidence that nutrition can shape biology at the molecular level,’ co-senior author Dr Max Storz said.
‘The next step is to understand whether these epigenetic changes persist over time and whether they translate into meaningful improvements in long-term health,’ Storz said, adding that will require larger clinical studies.
Roughly four percent of the US population follows a vegan diet, according to a poll by Statista.
Experts have said that the eating plan has a number of health benefits, and separate studies have shown that vegans are less likely to suffer from heart disease, diabetes and cancer than meat eaters.
However, some say that veganism can also trigger a number of harmful vitamin deficiencies.
Chief amongst these is a lack of vitamin B12 – a nutrient crucial for healthy blood vessels and brain function that is not found in plant-based foods like fruits, vegetables and grains.
Instead, vitamin B12 is primarily found in meat, fish, milk and eggs. Health officials advise that vegans take a daily vitamin B12 supplement.
